Commonly, a single radio is used for direct feeding of an antenna without the need of additional mounting and waveguide interconnecting elements. In this type of solution, the radio is directly supported at the antenna and its waveguide interface directly fits the antenna interface that serves the assigned polarization. The increase of link capacity can be obtained by polarization reuse, i.e., the transmission of a second channel with orthogonal polarization.
One solution of this type known in the art is the complete installation of a radio direct feeding antenna as used for the first channel. The drawback of this solution is that it is expensive due to the occupied space on the site. Quite often the space available at the sites is limited and therefore only a certain number of antennas can be installed to serve a dedicated link direction.
Another solution uses a common antenna serving both polarizations. Owing to the required access to the waveguide interfaces for both polarizations of state-of-the-art antennas, a direct feeding of the antenna with the two radios serving the orthogonal polarizations is no longer possible. Hence, the radios are separately mounted as close as possible to the antenna and the interconnection of radio and antenna RF interfaces is made by additional waveguide hardware as e.g. flexible waveguides. The separate mounting of the radios needs also a certain space close to the antenna and the additional waveguides will increase the insertion loss and therefore impair the link performance. Moreover, the separate mounting and waveguide hardware increases the cost of the solution.
Hence, an improved device for direct feeding orthogonal polarized waves of an antenna would be advantageous and in particular one that has good performance characteristics, compact size and is easy for manufacturing.